A remote radio unit (RRU) is a component of a base station, and is mainly configured to: perform downlink frequency conversion, filtering, and linear power amplifying on a baseband signal, and transfer the processed baseband signal to an antenna feeder. For uplink, the RRU performs filtering and low noise amplifying on a received uplink signal from a mobile terminal side, further performs amplifying, filtering, and down frequency conversion on a small radio frequency signal, and then completes analog-to-digital conversion, digital intermediate frequency processing, and the like.
From a perspective of a structure, the RRU includes an optical module (Small Form-factor Pluggables, SFP), a RRU mainboard, and a heat sink. The SFP and the RRU mainboard are disposed on a same big board and share the heat sink.
A temperature specification of a key device of the mainboard is usually from 105° C. to 125° C. (including 105° C. and 125° C.). However, a temperature specification of the SFP is usually from 85° C. to 90° C. (including 85° C. and 90° C.). A heat consumption ranging from 1 W to 2 W (including 1 W and 2 W) of the SFP causes a relatively small temperature rise. However, a heat consumption of the mainboard is large, and the large heat consumption causes a temperature rise of the heat sink at the SFP. Consequently, a temperature of the SFP exceeds the requirement of the specification.